In commonly assigned U.S. application Ser. No. 263,397 in the name of Jones and Weber, filed Oct. 27, 1988, entitled "Sustainer Propulsion System" and assigned to the same assignee as the instant application, the details of which are herein incorporated by reference, there is disclosed a missile including a sustainer engine. The sustainer engine is a thrust producing gas turbine which is employed to sustain the flight of the missile. However, to initiate the flight of the missile, it is common to use a rocket engine to provide sufficient boost for the purpose. Typically, the rocket engine will be a solid fuel rocket engine.
To launch the missile, the rocket engine is fired and either simultaneously, or shortly thereafter, the gas turbine engine is likewise started to provide sufficient thrust to sustain the flight of the missile to its target. In the usual case, a pyrotechnic device such as a convential start cartridge is employed to initiate operation of the gas turbine engine. Typically, the start cartridge is fired to generate gas under pressure and such gas under pressure is directed to the compressor or the turbine wheel or both to accelerate the engine rotor up to a speed where at its operation may be self-sustained, frequently 15 or 20% of rated speed. At that time fuel is admitted to the engine combustor and sustained combustion will occur to maintain operation of the engine and induce further acceleration up to rated speed. Conventionally, this requires the addition of a set of nozzles for introducing the gases from the start cartridge into the gas turbine that are in addition to the nozzle by which gases of combustion generated in the engine combustor are directed against turbine wheel.
In most any application of a gas turbine, it is desirable that the complexity of the components be minimized to reduce fabrication cost, minimize failure rates, increase the ease of servicing and the like. Where the gas turbine is employed in an airborne environment as in a cruise missile, it is further desirable that system weight be minimized so as to maximize payload, range, etc.
The present invention is directed to accomplishing those objectives.